Writeback min_capture map to TypeckResults

- Derive TypeFoldable on `hir::place::Place` and associated
  structs, to them to be written into typeck results.

Co-authored-by: Jennifer Wills <wills.jenniferg@gmail.com>
Co-authored-by: Logan Mosier <logmosier@gmail.com>

compiler/rustc_middle/src/ty/mod.rs

@@ -672,7 +672,18 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for TyS<'tcx> {
 #[rustc_diagnostic_item = "Ty"]
 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
 
-#[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable, HashStable)]
+#[derive(
+    Clone,
+    Copy,
+    Debug,
+    PartialEq,
+    Eq,
+    Hash,
+    TyEncodable,
+    TyDecodable,
+    TypeFoldable,
+    HashStable
+)]
 pub struct UpvarPath {
     pub hir_id: hir::HirId,
 }
@@ -680,7 +691,7 @@ pub struct UpvarPath {
 /// Upvars do not get their own `NodeId`. Instead, we use the pair of
 /// the original var ID (that is, the root variable that is referenced
 /// by the upvar) and the ID of the closure expression.
-#[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable, HashStable)]
+#[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable, TypeFoldable, HashStable)]
 pub struct UpvarId {
     pub var_path: UpvarPath,
     pub closure_expr_id: LocalDefId,
@@ -692,7 +703,7 @@ impl UpvarId {
     }
 }
 
-#[derive(Clone, PartialEq, Debug, TyEncodable, TyDecodable, Copy, HashStable)]
+#[derive(Clone, PartialEq, Debug, TyEncodable, TyDecodable, TypeFoldable, Copy, HashStable)]
 pub enum BorrowKind {
     /// Data must be immutable and is aliasable.
     ImmBorrow,
@@ -746,7 +757,7 @@ pub enum BorrowKind {
 
 /// Information describing the capture of an upvar. This is computed
 /// during `typeck`, specifically by `regionck`.
-#[derive(PartialEq, Clone, Debug, Copy, TyEncodable, TyDecodable, HashStable)]
+#[derive(PartialEq, Clone, Debug, Copy, TyEncodable, TyDecodable, TypeFoldable, HashStable)]
 pub enum UpvarCapture<'tcx> {
     /// Upvar is captured by value. This is always true when the
     /// closure is labeled `move`, but can also be true in other cases
@@ -763,7 +774,7 @@ pub enum UpvarCapture<'tcx> {
     ByRef(UpvarBorrow<'tcx>),
 }
 
-#[derive(PartialEq, Clone, Copy, TyEncodable, TyDecodable, HashStable)]
+#[derive(PartialEq, Clone, Copy, TyEncodable, TyDecodable, TypeFoldable, HashStable)]
 pub struct UpvarBorrow<'tcx> {
     /// The kind of borrow: by-ref upvars have access to shared
     /// immutable borrows, which are not part of the normal language
@@ -790,7 +801,7 @@ pub type RootVariableMinCaptureList<'tcx> = FxIndexMap<hir::HirId, MinCaptureLis
 pub type MinCaptureList<'tcx> = Vec<CapturedPlace<'tcx>>;
 
 /// A `Place` and the corresponding `CaptureInfo`.
-#[derive(PartialEq, Clone, Debug, TyEncodable, TyDecodable, HashStable)]
+#[derive(PartialEq, Clone, Debug, TyEncodable, TyDecodable, TypeFoldable, HashStable)]
 pub struct CapturedPlace<'tcx> {
     pub place: HirPlace<'tcx>,
     pub info: CaptureInfo<'tcx>,
@@ -799,7 +810,7 @@ pub struct CapturedPlace<'tcx> {
 /// Part of `MinCaptureInformationMap`; describes the capture kind (&, &mut, move)
 /// for a particular capture as well as identifying the part of the source code
 /// that triggered this capture to occur.
-#[derive(PartialEq, Clone, Debug, Copy, TyEncodable, TyDecodable, HashStable)]
+#[derive(PartialEq, Clone, Debug, Copy, TyEncodable, TyDecodable, TypeFoldable, HashStable)]
 pub struct CaptureInfo<'tcx> {
     /// Expr Id pointing to use that resulted in selecting the current capture kind
     ///